Acoustic signaling device



May 15, 1928.

1,669,827 R. o. Hoon ACOUSTIC SIGNALING DEVICE Filed Feb. 28, 1925 2 sheets-sheet 1 22 n, r'l

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El; 38 y2 May 15, 1928. 1,669,827

R. 0. HOOD ACOUSTIC SIGNALING DEVICE Filed Feb. 28, 1925 2 sheets-sheet 2 z8 a 34o A /0 /2 s 224 22 l /4/ f f Hyg. l v '-I (6 l l f o 1 l 42 l w l Jal l t 4g 76( v `soA Patented May l5,

l UNITED STATES PATENT 'oFI-ucE.

RALPH HOOD, F DANVEBS, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO vTHE M. & H. MFG. CO., OF WATERBURY, CONNECTICUT, A CORPORATION OF CONNECTICUT.

Application. filed February 28, 1 925. Serial No. 12,428.

This invention relates to acoustic signaling devices and especially to horns for Vehicles and has for an object the provision of a horn so constructed and arranged as to A emit a distinctive and pleasing signal.

A further object of the invention is generally to improve the construction and op; eration of acoustic signaling devices.

Fig. 1 is a side elevational View, partly 10 cut away, of an electrically actuated horn embodying the invention.

Fig. 2 is a longitudinal sectional elevational view of the horn shown in Fig. 1.

Fig. 3 is a transverse sectional elevational l5 view taken substantially along line 3-3 of Fig. 2.

Fig. 4 is a perspective view of a contact structure, which may be embodied in the horn as shown. v

20 Fig. 5 is a plan v-iew of a portion of an electromagnet structure such as may be used in the horn shown.

Fig. 6 is a sectional elevational view taken substantially along lines 6-6 of Fig. 5.

y Fig. 7 is a side elevational view of a ma e net core adapted for use with one of the v1- bratory diaphragms of the horn shown.

Fig. 8 is an enlarged detail view showing portions otl said contact structure. I

As hereshown, the horn-embodying the invention may include a casing having an enlarged cylindrical rear portion 10 and a reduced neck 12 extended forwardly from the enlarged cylindrical portion and termi.

nated in an open mouth 14. The'cylindrical portion 10 of the casing may include the rear wall 16 which wall is adapted to support the 1..,lhorn mechanism and comprises the rear clof Ysure for the casing. y Said wall may be pref- 40 erably internally concave and it is formed or provided with an annular cylindricaly flange 18. Said flange is adapted to tit within a corresponding flange 20 ot thecasing and besuitably detachably secured thereto by suitable means as the screws 22.

The sound-producing mechanism is disposed within the enlargedv cylindrical portion 10 of the enclosing casing and comprises essentially a drum having two opposed and spaced vibratory heads or Vdiaphragms between which is enclosed mechanism Afor vibrating them simultaneouslyl ACOUSTIC SIGNALING DEV'ICE.

As here shown, the drum includes a rear diaphragm or head 24 and aforward diaphragm or head 26 spaced from thediaphragm 24. Said diaphragms may be composed of suitable material as, for instance, sheet steel, and may b'e approximately identical in vibratory characteristics so that both may have substantially the same period of vibration. If desired, however, one of the diphragms may be different than the other in an obvious manner and so `proportioned with respect to the other that it will vibrate at some rate which bears such a relation to they vibrator-y period of the other that the resultant tone is composed oftwo mutually ha'rmonizing notesV and pleasing overtones thereof. Y

The diaphragmsmay be each provided with inturned rims 28 vand with flanges 30 outstanding .from said rims. The diaphragms may also be formed with axially extended circumferential anges 32 at the edges of said radially extending iianges for strengthening the diaphragm structure. The two diaphragms may be secured together as shown in Fig. 2 with the flanges 30 juxtaposed. Two separate gaskets 34 and 36 may be interposed between the diaphragm` flanges 3() to seal theenclosed space in a practically gas tight manner. The diaphragms may be clamped rigidly together in the relation illustrated in4 Fig. 2 by suitable means .as screwsv 38. Certain of said screws may extend through the rear wall 16 of the enclosing casing and spacing tubes 40 may be disposed on said screws and inter- HEISSUED posed between the drum and said wall 16 for support-ing said drum rigidly in respect to the rear wall of the casing and in spaced relation thereto so that there is a free acoustic passage between the inner diaphragm and the rear wall 16 and around the periphery of the drum to the neck 12 of the casing. A suitable supporting bracket 17 may be secured to the rear wall 16 or, if desired, the

screws 38 may extend directly .to a support, the horn casing being then omitted.

The electrically actuated mechanism for uio the diaphragms is contained between the diaphragms and is thereby substantially` sealed against dust and moisture. T he ac' tuating mechanism may include an electromagnet composed of two relatively flat laminated cores 42 and 44, which cores may be carried directly upon the diaphragms 24 and 26 respectively. Said cores may be formed or provided with opposed and spaced slots 46 therein in which an energizing winding 48 is received. Said energizing winding is adapted to be fixed in the slots of one of said cores as the slots ot core 42 and to protrude into the slots of, but being free from contact with. the core 44, thus permitting the two diaphragms to vibrate independently. Since the energizing coil 48 is carried by and thereby loads the diaphragm 24, it is desirable to compensate for the weight ofthe coil, and this is most conveniently done by removing an approximately equivalent weight of material from the core 42, as by forming a notch 50 therein of .suitable dimensions. The laminations of the cores may be secured in any well known manner or disposed between and secured ,to ears 52 which are struck out from a supporting disc 54; each core being provided with such a. dise. Fastening rivets 53 may extend through the laminations and the ear portions. The coil may be held in place by suitable bracket members 49 embracing the coil and bolted to the disc 54 (see Fig. 6). Said dises may be received in circular depressions or recesses 56 in the diaphragms and are secured in such relation by suitable means as rivets 58 passing through said discs and the diaphragm and through backing plates 60.y

The magnet cores 42 and 44 are adapted to be maintained normally in spaced relation as shown in Fig. 2 and are adapted to be attracted toward each other when the coil 48 is energized and the core, thereby, is magnetized. A make and break circuit controller may be provided to maintain the diapbragms in rapid vibration when the circuit through the energizing coil is Otherwise completed; and said make and brake mechanism is governed by the movements of the diaphragm. Said make and break mechanism may include a bracket 59 which is provided with ears 60 and 62, which ears are attached to one of the plates 54` as the plate carried by the rear diaphragm 24. A movable contact member 64 is fixed to a flexible flat spring-member 66 and said spring-member maybe formed with reflexed side edges 68 which serve to stiften said member at the area around the contact member. Said spring-member is carried b v and is insulated trom the bracket 59 by the insulating block 70. A stationary contact member 72 is secured to and carried by a channel member 74, which channel member may be also carried by the bracket 59. A metal plate 76 is disposed beneath and in electrical contact with the channel member 74 and said plate is formed with an outwardlj7 extended ear 78 to which one of the terminals of the magnet coil 48 is adapted to be secured. A similar plate 8() may be carried by the bracket 59 between and insulated from the contact member supports; and said plate is formed with a similar ear 82 to which the other terminal of the coil 48 is adapted to be connected.

The terminal leads may comprise conductors of suitable form such as tlat and flexible conducting strips 84 and 86 which are connected respectively with the spring member 66 and the plate 80. Said terminal leads are or may be provided with intermediate reflexed portions 88 and 90 to enhance the flexibility of .the leads and permit them to flex readily in response to vibratory movements of the diaphragms. Said terminal leads 84 and 88 may be extended outwardly at approximate right angles as shown at Fig. 3 and between the two packing gaskets 34 and 36 and may be connected electrically to appropriate terminals 92 and 94 carried by the rear wall of the enclosing casing.

The engagement and disengagement of the contact membersmay be controlled by relative vibration of the diaphragms. For this purpose, a screw 98 may be adjust-ably screwthreaded through the diaphragm 26 and also through plates 54 and 6() and may be locked in any set position by a check nut 100. Said screw is provided with a rod 102 of insulating material in its end and said rod is adapted to be disposed to engage the spring member 66 and separate the contact members when the diaphragms have been moved inwardly a predetermined distance thereby to break the energizing circuit.

As thus arranged both the adjusting screw and the contact members move inwardly and outwardly toward and away from each other with one cycle of movement for each vibration of the diaphragme. The adjusting screw is preferably so disposed as to be ascessible through the open end of the horn.

The structure herein shown is exceedingly simple and strong and unlikely to get out of order. Both diaphragms are vibrated simultaneously and the device emits a pleasing yet penetrating note of marked carrying power.

lVhile the invention has been described in detail with respect to a certain particular preferred example which gives satisfactory results, it will be understood by those skilled in the art after understanding the invention that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore` in the appended claims to cover all such changes and modifications.

What is claimed as new and is desired to be secured by Letters Patent of the United States is:

1. An acoustic signaling device including a pair of spaced independently-vibratory anism for said diaphragms comprising anl electro-magnet structure disposed between and having parts separately carried respectively by the free middle portions' of said diaphragms.

2. A warning horn including a pair of independently-vibratory diaphragms disposed in relatively closely spaced and generally parallel relation, means rigidly uniting the peripheral portionsl thereof to forni a substantially closed compartment between the diaphragme, means including a projector-casing surrounding and peripherallyspacedfrom and supporting said diaphragms yat the peripheral portions thereof with the bodies of said diaphragms mechanically substantially free to vibrate independently, and actuating means for said diaphragms disposed within said compartment.

3. An acoustic signaling device including a pair of diaphragms disposed in relatively closely spaced and generally parallel rela? tion, electromagnetic actuating means therefor. said diaphragms respectively having peripheral converging portions and radial flanges outwardly' extended between the proximate edges of said portions, clamping means passed through said flanges and sup- ,porting mea-ns for said diaphragms having connections with the flanges only thereof,

whereby to support said diaphragms for free vibration.

. 5. An acoustic signaling device including a pair of diaphragms disposed in relatively closely spaced and generally parallel relation, said diaphragms respectively having peripheral converging portions and radial abutting flanges outwardly extended between the proximate Aedges of said portions, portions and electro-magnetic actuating means..

for said diaphragms disposed between them, and a circuit lead extended from said actuabing means outwardly and clamped between the flanges of said diaphragme.

t3. An acoustic signaling device including a pair of diaphragms disposed in relatively closely spaced and vgenerally parallel relation, said diaphragms having peripheral converging portions, electro-magnetic actuating means for said diaphragms disposed between them, said converging portions being secured together with a gasket interposed therebetween, and a circuit lead extended from said actuating means and outwardly through said gasket.

7. An acoustic si alin a pair of substantially device including uplicate cup-like .independently-vibratory dia hragms having their edges secured togeter forming a chamber, peripheral supporting means for said diaphragms, and electro-magnetic actuatin means for and disposed between said diap ragms and including opposed magnet cores carried by and vibratable respectively with said diaphragms, and an energizing winding between the cores.

8. An acoustic signaling device including a pair of independently-vibratory diaphragms disposed in relatively closely spaced and generally parallel relation, peripheral supporting means for said diaphragms, and electro-magnetic actuating means for and disposed lbetween said diaphragms and including relatively fiat opposed magnet cores carried flatwise upon and vibratable with said diaphragms, said cores having opposed coil slots, and an energizing coil disposed in said slots, said coil being fixed in the slots in one core and free to vibrate in the slots of the other core. I

9. An acoustic signaling device including a pair of vibratory diaphragms, electromagnetic means for actuating said diaphragms with vibratory movement relative to each other, and al circuit controller for said electro-magnetic means comprising a pair of contact members carried by and movable with one of said diaphragms, and a control member-for said circuit controller carried by theother diaphragm.

10. An acoustic signaling device including a pair of vibratory diaphragms disposed in relatively closely spaced and generally parallel relation, electro-magnetic means carried by and disposed between said diaphragms to impart relative vibratory movement thereto, a circuit controller for said electro-magnetic means 'including a support carriedby one of said diaphragms, a pair of contactv members carried by said support, and a conl trol member for said contact members carried by said other diaphragm in position to engage with one of said contact members.

11. An acoustic signaling device including a. pair `of vibratory diaphragms having means securing the peripheries thereof rigidly together, gasket means interposed between the peripheral portions of said diaphragms, electro-magnetic actuating means for said diaphragms disposed between them, and `a circuit lead for said actuating means passing through said gasket means.

12. A warning horn including an enclosing casing, a drum having a pair of freely vibratory heads disposed within said casing, electromagnetic means having parts separately carried respectively by said heads for lll vibrating the same, and supporting means for said drum comprising means connecting said casing and the periphery only of said drum, a free acoustic passage being provided 6 between said drum and said casing.

13. A warning horn including a casing having an open mouth. a drum having a pair of freely vibratory heads disposed within but spaced from the walls of said casing,

10 electromagnetic means having parts separately carried respectively by said heads for vibrating the same, and supporting means within the casing for said drum, and permitting such free vibration of the heads, a

l16 free acoustic passage being provided from both vibratory heads to said mouth.

14. A. warning horn including a casing having an open mouth and an end wall opposite said mouth, means detachablv con- 20 necting said end wall with the body of said casing, a drum having two opposed freely having an open mouth and an end wall opposite said mouth, means detachably connecting said end wall with the body of said casing, a drum having two opposed freely vibratory heads disposed Within said ,casing opposite said mouth and adjacent said end .a circuit-controller for said wall` electromagnetic means having parts separately carried respectively by said heads for vibrating the same, and supporting means connecting the peripheral portions only of said drum with the casing, a free acoustic passage being provided from both heads to said mouth.

16. The combination of a pair of spaced and independently-vibratory diaphragms. electro-magnetic means to actuate them, and means. and means operatively connecting said circuit controller to both diaphragms, whereby the diaphragms act conjointly to control the circuit controller.

17. An electric signaling or alarm device comprising a pair'of similar independently vibratory diaphragms secured in respect to each other to form a housing for the operating parts of the device, said diaphragms having inflexible center portions of substantial area surrounded by iiexible annular areas. and a pair of cooperating substantially similar electro-magnet pole pieces secured respectively to the inside faces of said diaphragms at said inflexible areas.

18. An acoustical signaling device comprising a pair of opposed vibratory diaphragms having inflexible central portions, and electromagnetic actuating means and a current interrupter carried by said portions.

19. An acoustical signaling device comprising a pair of adjacent opposed and independently vibratory diaphragms, and electromagnetic actuating lneans therebetween comprising a pair of cooperating relatively thin flat. laminated core members secured respectively tlatwise to the center portions of the two diaphragms.

20. An acoustical signaling device comprising a pair of opposed vibratory cupshaped sheet metal members peripherally joined together and forming a complete enclosure, electrical actuating means therein and rigid supporting means for the device attached along the zone of juncture of said two members.

21. An acoustical signaling device comprising a pair of vibratory members of approximately equal periodicity, electromagnetic means for simultaneously vibrating said members in opposite phase relationship, and a current interrupter for said electromagnetic means actuated conjointly by said vibratory members.

Q2. In combination. a pair of independently and acoustically vibratory members of at least approximately equal natural periodicities` electromagnetic actuating means therefor acting upon each diaphragm independe-ntly` and means for initiatingr and maintaining a pulsating current. for said actuating means. the pulsations being synchronized with the vibrations of said members and of a frequency determined conjointly by the natural periodicities of said vibratory members.

23. An acoustical signaling device comprising a pair of opposed independently vibratory diaphragms of substantially equal periodicity. actuating means therefor comprising a cooperating pair of core members of substantially equal weight and separately carried respectively by said two diaphragms.

24. An electro-magnetically actuated warning signal comprising a housing having a chamber and a single sound outlet in direct air communication therewith. and two substantially independently vibratory disc members in the chamber having their vibratory areas free for substantially undampened vibration, and each supported from the chamber walls substantially concentrically in respect tov said outlet and both in air communication with said outlet. and electromagnetic means for causing actuation of said vibratory members.

25. An electro-magnetically actuated warning signal comprising a hollow disc-like housing or chamber having a sound outlet in direct air communication therewith, a pair of separately vibratory disc-like members in the chamber, each supported from the chamber walls, said members being mounted substantially in closely adjacent face-to-face relationship and substantially concentric and Hatwise in respect to the chamber end walls, at least one of said members being peripherally spaced from theV chamber walls to aii'ord air communication between the other member -and said outlet, and electromagnetic means` for causing actuation of said vibratory members.

26. A warning signal comprising a sound chamber, a vibratory diaphragm peripherally supported by the chamber walls and with its central area free for substantially undampened vibration, an electro-magnetic means for vibrating said diaphragm, a sound outlet for said chamber, another zand substantially separately vibratory member having an area free 'or Substantially undampened vibration and located in the chamber and supported thereby between said diaphragmand said outlet, said outlet being in air communication with said diaphragm and also with said other member for combining the sound waves and any beat frequencies produced thereby into a resultant warning signal.

27. An electro-magnetic signaling device comprising a. relatively flat substantially circular housing chamber formed of two cupshaped parts joined at their peripheries, a pair of complementary vibratory diaphragms joinedat their peripheries, electro-magnetic actuating means within the enclosure formed by said diaphragms, said diaphragms being substantially circular and arranged coaxially Within said chamber but spaced from the walls thereof, and supporting posts extending from the joined peripheries of the diaphragms to a wall of the housing.

28. A Warning signal comprising a relatively lat substantially circular housing formed of two parts joined at their peripheries, a pair of complementary vibratory diaphragms within said housing and also joined at their peripheries, the zones of juncture of the housing parts and said diaphragms being substantially concentric and closely adjacent, means for, supporting the diaphragms within the housing, and electromagnetic actuating means'within the enclosure formed by said diaphragms.

In testimony whereof, I have signed my name to this specification. RALPH O. HOOD. 

